The goals of the Irradiation Core are to provide precise ex-vivo (human blood) and in-vivo (mice) irradiations with accurate dosimetry. The Irradiation Core will provide: whole body mouse blood irradiations spanning a dose-rate range of 6 orders of magnitude, internal 137Cs exposures at the Lovelace Respiratory Research Institute, exposures of blood and mice to neutrons with an energy spectrum mimicking that of a nuclear detonation and whole thorax irradiations of mice. Central to reliable and reproducible irradiation and dosimetry is an effective quality control system. The Irradiation Core already has in place a series of SOPs covering operation and dosimetry both for our standard irradiation sources as well as the non-standard CMCR-specific irradiation sources, such as the low dose rate animal irradiator and the IND-spectrum neutron irradiator. The Core will continue writing SOPs for the new irradiation and dosimetry modalities proposed to ensure their reliable and repeatable use and will collaborate with the Radiation Physics Core to ensure that these SOPs are in accord with the accepted irradiation procedures across the CMCRC. While standard dosimetric techniques will be used for most experiments, the Core will develop new technologies to address the challenges of some of the proposed irradiation modalities. Organ dosimetry and validation will be performed using a unique heterogeneous mouse phantom, microMOSFET dosimetry, and Gafchromic film. In-vivo dosimetry for long-term experiments, where mice are not restrained, will be performed using encapsulated ?pin worm? TLDs injected subcutaneously. The Core will also develop, fabricate, test, and perform dosimetry of two new irradiation modalities, specific to CMCR exposure scenarios. Specifically, a very-high dose-rate (2 Gy/sec) irradiator based on a radiotherapy linear accelerator and a continuously-decreasing-dose-rate external 137Cs mouse irradiator to simulate either internal-emitter 137Cs exposure or the (constant) external exposure from environmental contamination. This will dramatically increase the practicality and cost-effectiveness of internal-emitter 137Cs-based research throughout our (and other) CMCR programs.